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                [Usaco2009 Feb]The Leprechaun 寻宝                </h1>
                <p>时间限制：2s&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;  空间限制：64MB</p>			</div>
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                                <h3>题目描述</h3><p><div><span style="font-size: medium">你难以想象贝茜看到一只妖精在牧场出现时是多么的惊讶．她不是傻瓜，立即猛扑过去，用她那灵活的牛蹄抓住了那只妖精．</span></div>
<div><span style="font-size: medium">&nbsp;&nbsp;&nbsp;&nbsp;&ldquo;你可以许一个愿望，傻大个儿！&rdquo;妖精说．</span></div>
<div><span style="font-size: medium">&nbsp;&nbsp;&nbsp;&nbsp;&ldquo;财富，&rdquo;贝茜用梦游般的声音回答道，&nbsp;&nbsp;&ldquo;我要获得财富的机会．&rdquo;</span></div>
<div><span style="font-size: medium">&nbsp;&nbsp;&nbsp;&nbsp;妖精从来没有碰到过这么简单的愿望．他在地方划出一大块N&times;N(1&le;N&le;200)的方格，每个格子上写上_1,000,000到1,000,000之间的数字．他说：&nbsp;&nbsp;&ldquo;在方格上朝一个方向行走，可以是行的方向，列的方向，斜对角的方向，一步只能走一格，所有你踩过的数字的和就是你的财富．&rdquo;</span></div>
<div><span style="font-size: medium">&nbsp;&nbsp;&nbsp;&nbsp;贝茜请你来帮忙，找到一行、一列或一条对角线上找一段连续的数字，它们的和最大．由于妖精方格的神奇特性，沿着一个方向走，走到了边际，再一步跨过去可以&ldquo;绕&rdquo;到方格的对边出现．一行两端的格子是相邻的，一列两端的格子也是相邻的，甚至相邻两行的分别两端的格子也是相邻的（斜对角方向）．</span></div>
<div><span style="font-size: medium">&nbsp;&nbsp;&nbsp;&nbsp;对于下图左边的方格，所有标记过的数字都在一条对角线上．</span></div>
<div><span style="font-size: medium">&nbsp;&nbsp;<img height="132" alt="" width="353" src="../file/1723_0.jpg" /></span></div>
<div><span style="font-size: medium">&nbsp;</span></div>
<div><span style="font-size: medium">对于这个方格，能踩出来的最大的和是24，踩过的数字在右图中标记出来了</span></div></p><hr/><h3>输入格式</h3><p><div><span style="font-size: medium">&nbsp;&nbsp;&nbsp;&nbsp;第1行输入N，之后输入N行N列的矩阵．</span></div></p><hr/><h3>输出格式</h3><p><div>&nbsp;</div>
<div><span style="font-size: medium">&nbsp;&nbsp;&nbsp;&nbsp;输出最大的和．</span></div></p><hr/><h3>样例输入</h3><pre>4
8 6 6 1
-3 4 0 5
4 2 1 9
1 -9 9 -2</pre><hr/><h3>样例输出</h3><pre>24</pre><hr/><h3>提示</h3><p>没有写明提示</p><hr/><h3>题目来源</h3><p>Silver</p>
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